The material for producing chips such as CPU is semiconductor, and the main material is silicon Si. In the process of purifying silicon, the raw material silicon will be melted and put into a huge timely furnace. At this time, the seed crystal is put into the furnace, so that the silicon crystal can grow around the seed crystal until almost perfect monocrystalline silicon is formed.

2, cutting the wafer

Silicon ingots are made, molded into a perfect cylinder, and then cut into small pieces, called wafers. Wafers are really used in the manufacture of CPU.

Wafer cutting machine cuts a silicon wafer with a predetermined specification from a monocrystalline silicon rod and divides it into a plurality of small areas, each of which will become the core of a CPU. Generally speaking, the thinner the wafer is cut, the more CPU products can be made with the same amount of silicon material.

3. Photocopying (Photolithography)

A photoresist substance is coated on a silicon oxide layer obtained by heat treatment. Ultraviolet rays irradiate the silicon substrate through the template printed with the complex circuit structure pattern of CPU, and the photoresist substance dissolves at the place irradiated by ultraviolet rays.

In order to avoid the interference of light in areas that do not need to be exposed, masks must be made to cover these areas. This is a rather complicated process, and the complexity of each mask should be described by the data of 10GB.

Step 4 etch prints

Etching uses ultraviolet light with short wavelength and a large lens. Light with short wavelength will pass through the holes of these time masks and shine on the photoresist film to expose it. Next, stop the irradiation and remove the mask, and use a specific chemical solution to wash off the exposed photoresist film and a layer of silicon next to the resist film.

Then, the exposed silicon will be bombarded by atoms, so that the exposed silicon substrate will be locally doped, thus changing the conductive state of these regions and manufacturing N-wells or P-wells. Combined with the substrate made above, the gate circuit of CPU is completed

5. Repetition and stratification

In order to process a new layer of circuit, silicon oxide is grown again, then a layer of polysilicon is deposited, coated with photoresist, and the photocopying and etching processes are repeated to obtain the trench structure containing polysilicon and silicon oxide. Repeat many times to form a 3D structure, which is the core of the final CPU. The middle of each layer should be filled with metal as a conductor.

Intel's Pentium 4 processor has seven layers, while AMD's Athlon 64 has nine layers. The number of layers depends on the layout of CPU at design time and the current passing through it.

6. Packaging

At this time, the CPU is a wafer, and users cannot use it directly. It must be sealed in a ceramic or plastic shell so that it can be easily installed on the circuit board. The package structure is different, but the more advanced the CPU package, the more complicated it is. New packaging can often improve the electrical performance and stability of the chip, indirectly providing a solid and reliable foundation for the promotion of the main frequency.

7. Multiple tests

Testing is an important part of CPU manufacturing, and it is also a necessary test before CPU leaves the factory. This step will test the electrical properties of the wafer to see if there are any errors and in which step (if possible) these errors occurred. Next, each CPU core on the wafer will be tested separately.

Due to the complex structure and high density of SRAM (Static Random Access Memory, the basic component of cache in CPU), cache is a part of CPU that is prone to problems, and cache testing is also an important part of CPU testing.

Each CPU will be thoroughly tested to verify all its functions. Some CPUs can run at higher frequencies, so they are marked with higher frequencies; However, some CPUs are marked with low frequency because of their low running frequency for various reasons.

Finally, a single CPU may have some functional defects. If the problem lies in the cache, the manufacturer can still block part of its cache, which means that this CPU can still be sold, but it may be a low-end product such as Celeron.

Before the CPU is boxed, it is usually tested for the last time to ensure that the previous work is accurate. According to the maximum running frequency and cache determined before, put them into different packages and sell them all over the world.

Extended data

Main forms of CPU control technology

1, select the control. The operation of centralized processing mode is realized on the basis of specific program instructions to meet the needs of computer users, and CPU can choose according to the actual situation in the operation process to meet the data flow needs of users. The important role of command and control technology. Formulating the operation mode according to the user's needs can well maintain the orderly formulation of data instruction actions.

In the process of CPU execution, the instructions of the program are executed smoothly, and only by keeping them in a certain order can the use effect of the computer be guaranteed. CPU is mainly used to automatically process data sets, which is the key to realize centralized control, and its core is instruction control operation.

2. Insert the control. The operation control signal generated by CPU is mainly realized by the function of instructions, and the purpose of controlling these components is achieved by sending instructions to the corresponding components. The realization of instruction function is mainly accomplished through a series of operations performed by components in the computer. More small control elements are the key to build a centralized processing mode in order to better complete CPU data processing operations.

3. Time control. Applying time counting to various operations is called time control. When executing instructions, it should be completed within the specified time. The instructions of the CPU are fetched from the cache or memory, and then the instructions are decoded, mainly in the instruction register. In this process, it is necessary to strictly control the program time.

Baidu encyclopedia -CPU

Baidu encyclopedia -CPU manufacturing process